They were also more likely than others to be taking medication for mental health problems.

Professor Michael King, from University College London, and his fellow researchers wrote in the British Journal of Psychiatry: "Our main finding is that people who had a spiritual understanding of life had worse mental health than those with an understanding that was neither religious nor spiritual."

The study was based on a survey of 7403 randomly selected men and women in England who were questioned about their spiritual and religious beliefs, and mental state.